Control of size and morphology in NiO particles prepared by a low-pressure spray pyrolysis

Nickel oxides (NiO) nano- and submicron particles were synthesized by a low-pressure spray pyrolysis system. Conversion of micrometer droplets into particles in the gas phase using NiO synthesis as a model was studied. Different types of precursors (aqueous Ni(NO3)2·6H2O, NiCl2, and Ni(HCO2)2·2H2O) and temperatures from 400 to 900 °C have great influences on controlling the size and morphology of final particles. The results show that operation of a low-pressure system leads to substantial changes in size and morphology of particles, and that the NiO particles having size around 20 nm can be generated under a limited of conditions.